You can download the model for free: https://sketchfab.com/surok.zdes/models
Original Reference: http://conceptartworld.com/artists/adam-baines/
This is my second model made for game engines, I'm not a professional and I can make mistakes, 3D modeling is just my hobby)
I hope someday I will be able to work in GameDave studio, but for now I am developing my skills and trying to become better)
If you have any questions about copyright, please email me at: surok.zdes@gmail.com
Have a nice day everyone!) Do not forget to wash your hands with soap and water, and I will go to sleep after the work done :)
P.S. On the model in the Sketchfab, above the butt of the weapon, there is a bug, strange, but in the Marmoset and UnrealE4 there is no such thing, most likely the site itself has ruined it)